gnome-shell crashed with signal 5

[Rachel Greenham]

Have been using this system on a normal non-hidpi monitor (via displayport) for weeks, since installing 18.04 alpha from scratch.

Just plugged it into a 4K monitor, also via displayport. The system was shut down while I moved it to the different desk, so it was switched on to the new monitor, not a live swap.

System booted, everything came up, logged in, everything seems fine, including my gnome shell, which is running, but this bug report came up too.

ProblemType: Crash
DistroRelease: Ubuntu 18.04
Package: gnome-shell 3.27.92-0ubuntu1
ProcVersionSignature: Ubuntu 4.15.0-10.11-generic 4.15.3
Uname: Linux 4.15.0-10-generic x86_64
ApportVersion: 2.20.8-0ubuntu10
Architecture: amd64
CurrentDesktop: GNOME-Greeter:GNOME
Date: Thu Mar 8 16:12:40 2018
DisplayManager: gdm3
ExecutablePath: /usr/bin/gnome-shell
GsettingsChanges:

InstallationDate: Installed on 2018-02-20 (16 days ago)
InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Alpha amd64 (20180214)
ProcCmdline: /usr/bin/gnome-shell
ProcEnviron:
 LANGUAGE=en_GB:en
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_GB.UTF-8
 SHELL=/bin/false
Signal: 5
SourcePackage: gnome-shell
StacktraceTop:
 () at /usr/lib/x86_64-linux-gnu/libmutter-2.so.0
 _XIOError () at /usr/lib/x86_64-linux-gnu/libX11.so.6
 _XReply () at /usr/lib/x86_64-linux-gnu/libX11.so.6
 XSync () at /usr/lib/x86_64-linux-gnu/libX11.so.6
 () at /usr/lib/x86_64-linux-gnu/libgdk-3.so.0
Title: gnome-shell crashed with signal 5
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups:

[Apport retracing service (apport)]

Thank you for taking the time to report this crash and helping to make this software better. This particular crash has already been reported and is a duplicate of bug #1748450, so is being marked as such. Please look at the other bug report to see if there is any missing information that you can provide, or to see if there is a workaround for the bug. Additionally, any further discussion regarding the bug should occur in the other report. Please continue to report any other bugs you may find.